• B-Cycle, a Wisconsin company with bike-sharing stations in Chicago, Houston, Nashville, Des Moines, Iowa, Charlotte, N.C., Kansas City, Mo., Madison, Wis., Denver and Boulder, Colo., as well as Broward County and Hawaii.

• CycleHop, which says it has 20 years of experience in bike-sharing programs. Through a sister company, it has maintained and operated fleets of rental bikes for communities that include New York, Chicago, Miami, San Francisco and Washington, D.C. It also has worked with B-Cycle in Broward County, according to its website.

• DecoBike, which has programs in Miami Beach, where it is based, plus Surfside and Long Beach, N.Y.

Each company submitted a serious proposal and has experience setting up successful bike-sharing programs, Buckhorn said in announcing the bids.

"I look forward to exploring the details," he said.

Tampa's goal is to have 30 stations with 300 rentable bikes throughout downtown, Ybor City and surrounding neighborhoods in fall 2013. The program could be expanded to the West Shore business district and the University of South Florida area by fall 2015.

As proposed, riders would pay a monthly or annual membership fee or use their cellphones or credit cards to rent the bikes on an hourly basis. City officials have said they expect that, typically, there would be no fee if the bikes were used for a half-hour or less.

City officials also envision creating a dual-pricing structure so that commuters coming off buses — or, in the future, other forms of mass transit — could use the bikes for the last mile of their trip.

The use of a cellphone or credit card to rent the bikes would be expected to reduce theft — the fatal flaw of an earlier Tampa bike-sharing effort.

In 1997, city officials salvaged about 50 unclaimed bikes from police inventory, painted them traffic-cone orange and left the "Orangecycles" unlocked throughout downtown for anyone to ride. Within weeks, every bike was gone.

Since then, bike-sharing programs have begun using advanced tracking and locking mechanisms and software for monitoring the bikes' use.